As-milled Powders Research Articles

The production of nanocrystalline AlCoCrFeNiTiZn high entropy alloy via mechanical alloying: Study of the formation mechanism, microstructural evolution, and magnetic properties of the alloy

In this paper, AlCoCrFeNiTiZn high-entropy alloy was produced in the powder and bulk form using the mechanical alloying and sintering processes. The sintering process was carried out in a tube furnace with controlled atmosphere on the cold-pressed alloyed powders which were obtained after 120 h of ball milling. The microstructures and properties of the as-milled powders and as-sintered samples were investigated using X-ray diffraction, scanning electron microscopy, transmission electron microscopy, differential scanning calorimetry, and vibrating sample magnetometry techniques. The results revealed that both the final milled products and the as-sintered bulk HEA are composed of FCC and BCC solid solutions. The bulk alloy obtained during sintering possessed a relative density above 83% of theoretical maximum density. According to the magnetometry results, both as-milled AlCoCrFeNiTiZn powders (120 h) and as-sintered bulk HEA present good semi-hard magnetic properties and have 40.36 and 32.94 emu/g, saturation magnetization, 114.84 and 216 Oe intrinsic coercivity and 10.59 and 7.05 emu/g remanent magnetization, respectively.

Alloying behavior and characterization of (CoCrFeNiMn)90M10 (M=Al, Hf) high-entropy materials fabricated by mechanical alloying

The alloying behavior and microstructures of the (CoCrFeNiMn)90M10 (M=Al, Hf) high-entropy alloy (HEA) powders fabricated by mechanical alloying were studied. The CoCrFeNiMn)90Al10 powders have duplex solid-solution structures. In contrast, nanocrystalline HfNi3 anchoring in amorphous structures is found in the (CoCrFeNiMn)90Hf10 powders. The (CoCrFeNiMn)90Al10 powders show better ferromagnetic behaviors, mainly explained by the facilitated motion of the magnetic domain induced by the coherent interface between duplex phases. Combined with our previous work, the rules of forming solid-solution and amorphous phase in as-milled HEA powders are preliminarily proposed. It is found that, compared with the as-cast HEA reported previously, the variation range of mixing enthalpy with atomic size difference of the solid-solution formed in as-milled HEA powders is broader. Moreover, the variation ranges between mixing enthalpy and entropy with atomic size difference of the amorphous phase in HEA powder become wider than those of high-entropy bulk metallic glass.

The Effect of Cu Additions on the Antibacterial Properties of Metallic Glassy Ni50TM50 (TM; Ti, Zr) Binary Systems

Antibacterial agents derived from classic organic compounds have been frequently employed for a number of years as a protective layer for biofilms. On the other hand, these agents often comprise dangerous components that, due to their interaction with toxic compounds, may be damaging to human beings. This hazard may be caused by the agents’ proximity to the toxic substances. Over the course of the past three decades, a variety of approaches, such as the utilization of a broad spectrum of metallic and oxide materials, have been the subject of research in order to develop a diverse selection of antibacterial coating layers that are acceptable. One of these approaches is the use of silver nanoparticles. It has been established that the cold spray technique, a solid-state method compatible with nanopowders, has shown higher performance and is the most effective strategy for coating materials. This has been proven via testing. It is possible to produce one-of-a-kind material coatings in ways that are not even remotely imaginable with any other thermal coating method, which is the primary reason for its prominence in contemporary production. The capacity to do so is what provides it with an advantage over its rivals in the market. This current study was conducted, in part, to investigate the effects of Cu-alloying elements on the antibacterial behavior of metallic glassy alloys on Ni50TM50 (TM; Ti, Zr) and Cu50TM40Ni10 (TM; Ti, Zr) systems prepared by the mechanical disordering technique, in conjunction with the cold spray method. These alloys were created by combining the mechanical disordering technique with the cold spray method. The arc melting process was employed to generate master alloys consisting of Ni50Ti50, Ni50Zr50, Cu50Ti40Ni10, and Cu50Zr40Ni10 for the purpose of this investigation. The master alloys were then used as feedstock materials for the creation of metallic glassy powders. Following the pulverization of the alloys of each system into a powdered form, the mixtures were charged through a high-energy ball milling operation for a duration of 50 h. Using the cold spray technique, the as-milled powders, which were metallic glasses, were applied singly in order to coat SUS304 sheets. The method was employed for this purpose. After the addition of Cu to the two binary Ni50TM50 (TM; Ti, Zr) alloys, the antibacterial properties of their corresponding metallic glassy phases were found to be significantly enhanced. This was shown by the fact that they were successful in preventing the development of biofilm by E. coli in contrast to the other systems that were evaluated.

Crystallization kinetics of Cu50Zr40Ti10 amorphous powder

The non-isothermal and isothermal crystallization behaviors are systematically investigated for the gas-atomized and as-milled amorphous alloy powders. The results show that the crystallization phase is Cu10Zr7 phase for the gas-atomized and as-milled amorphous alloy powders in non-isothermal and isothermal crystallization modes. The glass transition temperature, onset crystallization temperature, and crystallization peak temperature are larger for the as-atomized alloy powders than for the as-milled ones. The activation energies for the glass transition and crystallization are lower for the as-atomized alloy powders than for the as-milled ones. The crystallization mechanism of the gas-atomized and as-milled amorphous alloy powders nearly depends on the heating rates and the annealing temperatures. The detailed crystallization mechanism of non-isothermal and isothermal modes are discussed.

Effect of the addition of Y and Y2O3 on microstructure and mechanical properties of 15Cr-15Ni ODS steel

15Cr-15Ni ODS steels with the addition of Y or Y2O3 were fabricated via the mechanical alloying and hot isostatic pressing, followed by forging treatment (named as 15Cr-15Ni-Y and 15Cr-15Ni-Y2O3, respectively). The morphology of as-milled powders of 15Cr-15Ni-Y was flatter than that of 15Cr-15Ni-Y2O3. As-forged samples were characterized by high-resolution transmission electron microscope. The oxide particles in both 15Cr-15Ni-Y and 15Cr-15Ni-Y2O3 ODS steels were identified as δ-Y4Zr3O12. The mean size and number density of dispersed nanoparticles in 15Cr-15Ni-Y and 15Cr-15Ni-Y2O3 ODS steels were 13.6 nm, 2.5 × 1022/m3 and 12.8 nm, 5.5 × 1022/m3, respectively. The tensile test at room temperature and 700℃ indicated that the tensile strength of 15Cr-15Ni-Y was lower than that of 15Cr-15Ni-Y2O3 ODS steel, while the total elongation of 15Cr-15Ni-Y was higher. The theoretical value based on the strengthening mechanism was calculated and discussed as well.

Enhanced Electromagnetic-Wave Absorbing Performances and Corrosion Resistance via Tuning Ti Contents in FeCoNiCuTix High-Entropy Alloys.

Efficient and stable electromagnetic-wave (EMW) absorption materials have attracted great attention in the field of reducing microwave pollution. Herein, FeCoNiCuTix high-entropy alloys (HEAs) as electromagnetic-wave absorbing materials were prepared by a high-energy ball-milling method. The as-milled HEA powders presented a flaky shape with a high aspect ratio. Impedance matching was efficiently optimized by severe lattice distortion, which was caused by Ti incorporation. The introduced plentiful defects in FeCoNiCuTix HEAs provided abundant polarization sites for dielectric loss. By tuning Ti contents, FeCoNiCuTi0.2 HEAs delivered excellent EMW absorption performances. The maximal reflection loss (RLmax) values reached -47.8 dB at 10.86 GHz as thin as 2.16 mm, and the widest bandwidth was 4.76 GHz (5.97-10.73 GHz). Furthermore, the introduction of Ti enhanced corrosion resistance via increasing the charge transfer resistance of a passivated film. Those characteristics of FeCoNiCuTix HEAs made these materials a practical gigahertz-range EMW absorber. Additionally, our findings provided a facile and tunable strategy for designing EMW absorbing materials, which was aimed at lightweight, highly efficient absorption, and resistance to harsh environments.

The effect of Ni and Ti additions on the glass forming ability and magnetic properties of Al-Fe-Y alloy prepared by mechanical alloying

Amorphous Al82Fe14Ni2Y2 and Al82Fe14Ti2Y2 alloys were synthesized by mechanical alloying. Morphological and structural characterizations of the powders, milled for different periods of time, were investigated by scanning electron microscopy and X-ray diffraction methods. The dissolution of Ni and Al into the Fe lattice led to the formation of Fe(Ni,Al) solid solutions in Al82Fe14Ni2Y2 alloy after 20 h of milling. A slower dissolution of Ti and Al into the Fe lattice can be observed for Al82Fe14Ti2Y2 after milling 40 h. The fully amorphous structure can be obtained for Al82Fe14Ni2Y2 after 60 h of milling. The amorphization of the Al82Fe14Ti2Y2 sample milled for 100 h was not complete, and a partially nanocrystal phase of Ti was still present. Coercivity (Hc) and the saturation magnetization (Ms) of as-milled powders decreased markedly with increasing milling time. The magnetic properties of the alloys were consistent with the structural changing during milling process. The amorphous phase transforms into fcc-Al and metallic compounds after annealed DSC treatment.

Synthesis and sintering of Fe-32Mn-6Si shape memory alloys prepared by mechanical alloying

Fe-32Mn-6Si alloy was produced using the mechanical alloying (MA) process of high purity powders under an inert argon gas atmosphere. The aim of this investigation is the in-depth study of the microstructure and phase transformation during the milling-sintering process of Fe-32Mn-6Si shape memory alloys. During the milling process, a significant amount of amorphous phase was created as well the crystalline martensite and austenite phases. The amorphous phase was increased by milling time enhancement and then it was decreased due to the mechano-crystalization phenomenon. It was detected that the microhardness of the alloyed powder directly depends on the amount of the amorphous phase. Furthermore, the particle size of as-milled powder firstly decreased and then increased, when the amorphous phase cojoined gradually during the milling process the transformation of martensite into austenite. The lattice strain was increased considerably during the milling process which was a reason for martensite phase creation resulting in the high shape memory properties. The amount of pre-strain for Fe-32Mn-6Si alloy was calculated to be 3.3%. Furthermore, the optimum sintering temperature was approved to be 950 °C by reduction of the percentage of pores and suitable densification.

Effects of Preparation Procedures and Porosity on Thermoelectric Bulk Samples of Cu2SnS3 (CTS).

The thermoelectric behavior and stability of Cu2SnS3 (CTS) has been investigated in relation to different preparations and sintering conditions, leading to different microstructures and porosities. The studied system is CTS in its cubic polymorph, produced in powder form via a bottom-up approach based on high-energy reactive milling. The as-milled powder was sintered in two batches with different synthesis conditions to produce bulk CTS samples: manual cold pressing followed by traditional sintering (TS), or open die pressing (ODP). Despite the significant differences in densities, ~75% and ~90% of the theoretical density for TS and ODP, respectively, we observed no significant difference in electrical transport. The stable, best performing TS samples reached zT ~0.45, above 700 K, whereas zT reached ~0.34 for the best performing ODP in the same conditions. The higher zT of the TS sintered sample is due to the ultra-low thermal conductivity (κ ~0.3–0.2 W/mK), three-fold lower than ODP in the entire measured temperature range. The effect of porosity and production conditions on the transport properties is highlighted, which could pave the way to produce high-performing TE materials.

Synthesis and characterization of the novel nanostructured NiC carbide obtained by mechanical alloying

In the present work, a comprehensive study of mechanical alloying of Ni-carbon nanotubes (CNT) and Ni-Graphite equiatomic powder mixtures under the same technological modes has provided to reveal the features of using different types of carbon (CNT or graphite) as a charge component. The as-milled powders were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) and magnetometric study. A novel nanoscale fcc NiC monocarbide was synthesized regardless the type of the charge used. According to the XRD study the formation of this phase takes place in two stages. A two-step carbide formation mechanism has been proposed. The associated changes in the nickel lattice, such as changes in the lattice parameter, lattice strain and residual stresses, which led to the formation of NiC monocarbide were also evaluated and discussed. Parameters of the electronic structure of NiC were calculated using the MStudio MindLab 7.0 software package with the experimental data on the crystal structure of the NiC phase obtained as input. Temperature dependencies of magnetic susceptibility of NiC synthesized have been studied up to 950 K. Carbides synthesized were found to be weak ferromagnets at the room temperature and their Curie temperature TC ranges within 670 – 725 K. The calculated value of the magnetic moment per nickel atom (2.83μB) is higher than that of a bulk Ni (1.3μB). Likely, the observed increase of μ is caused by the presence of a certain amount of residual single-domain ferromagnetic Ni nanoparticles in the samples synthesized.

Effect of Tantalum Pentoxide Addition on the Radiopacity Performance of Bi2O3/Ta2O5 Composite Powders Prepared by Mechanical Milling.

Among the various phases of bismuth oxide, the high temperature metastable face-centered cubic δ phase attracts great attention due to its unique properties. It can be used as an ionic conductor or an endodontic radiopacifying material. However, no reports concerning tantalum and bismuth binary oxide prepared by high energy ball milling and serving as a dental radiopacifier can be found. In the present study, Ta2O5-added Bi2O3 composite powders were mechanically milled to investigate the formation of these metastable phases. The as-milled powders were examined by X-ray diffraction and scanning electron microscopy to reveal the structural evolution. The as-milled composite powders then served as the radiopacifier within mineral trioxide aggregates (i.e., MTA). Radiopacity performance, diametral tensile strength, setting times, and biocompatibility of MTA-like cements solidified by deionized water, saline, or 10% calcium chloride solution were investigated. The experimental results showed that subsequent formation of high temperature metastable β-Bi7.8Ta0.2O12.2, δ-Bi2O3, and δ-Bi3TaO7 phases can be observed after mechanical milling of (Bi2O3)95(Ta2O5)5 or (Bi2O3)80(Ta2O5)20 powder mixtures. Compared to its pristine Bi2O3 counterpart with a radiopacity of 4.42 mmAl, long setting times (60 and 120 min for initial and final setting times) and 84% MG-63 cell viability, MTA-like cement prepared from (Bi2O3)95(Ta2O5)5 powder exhibited superior performance with a radiopacity of 5.92 mmAl (the highest in the present work), accelerated setting times (the initial and final setting time can be shortened to 25 and 40 min, respectively), and biocompatibility (94% cell viability).

Laser-Sintered Mg-Zn Supersaturated Solid Solution with High Corrosion Resistance.

Solid solutions of Zn as an alloy element in Mg matrixes are expected to show improved corrosion resistance due to the electrode potential being positively shifted. In this study, a supersaturated solid solution of Mg-Zn alloy was achieved using mechanical alloying (MA) combined with laser sintering. In detail, supersaturated solid solution Mg-Zn powders were firstly prepared using MA, as it was able to break through the limit of phase diagram under the action of forced mechanical impact. Then, the alloyed Mg-Zn powders were shaped into parts using laser sintering, during which the limited liquid phase and short cooling time maintained the supersaturated solid solution. The Mg-Zn alloy derived from the as-milled powders for 30 h presented enhanced corrosion potential and consequently a reduced corrosion rate of 0.54 mm/year. Cell toxicity tests confirmed that the Mg-Zn solid solution possessed good cytocompatibility for potential clinical applications. This study offers a new strategy for fabricating Mg-Zn solid solutions using laser sintering with MA.

Microstructural and Magnetic Behavior of Nanocrystalline Fe-12Ni-16B-2Si Alloy Synthesis and Characterization

The nanocrystalline Fe70Ni12B16Si2 (at.%) alloy was prepared by mechanical alloying (MA) of elemental powders in a high-energy planetary ball mill. Phase evolution, microstructure, thermal behavior and magnetic properties were investigated. It was found that a body-centered cubic structured solid solution started to form after 25 h milling and a faced-centered cubic structure solid solution started to form after 50 h of milling; its amount increased gradually with increasing milling time. The BCC and the FCC phases coexisted after 150 h of milling, with a refined microstructure of 13 nm and a 10 nm crystallite size. The as-milled powder was annealed at 450 °C and 650 °C and then investigated by vibrating sample magnetometry (VSM). It was shown that the semi-hard magnetic properties are affected by the phase transformation on annealing. The saturation magnetization decreases after annealing at 450 °C, whereas annealing at 650 °C improves the magnetic properties of 150 h milled powders through the reduction of coercivity from 109 Oe to 70 Oe and the increase in saturation magnetization.

Synthesis and Characterization of FeNi-based Composite Powder from the Mixture of Fe-based Amorphous Powders and Crystalline Ni powders

Fe–Ni alloys have attracted interest as important magnetic alloys without rare-earth (RE) elements, which exhibit a wide variety of magnetic properties depending on the atomic ratios of Fe and Ni. Here, we attempted to synthesize Fe-Ni magnetic materials using a Fe based amorphous alloy precursor that is thermodynamically metastable and has more open atomic packing structure than crystalline alloys. High energy ball milling was applied to promote the formation of various Fe-Ni phases using mixtures of the amorphous precursor powder and 10-50% crystalline Ni powder. The as-milled composite powders as well as the composite powders annealed at 673 K were analyzed by X-ray diffractometer, differential scanning calorimeter, scanning electron microscope, and vibrating sample magnetometer to investigate their magnetic properties in terms of phase transformation behavior of the composite powders.

Enhanced magnetocaloric effect in Fe-rich (NixFe1-x)70.5B17.7Si7.8Ti4 (x = 0.3 and 0.4) mechanically alloyed nanocrystalline powder

We report the evolution of nanocrystalline α-Fe and γ-Ni phases in (NixFe1-x)70.5B17.7Si7.8Ti4 (at.%) where, x = 0.3 and 0.4, upon mechanical alloying of elemental powder mixtures up to 36 h. The effect of milling time on the nanostructure evolution, thermal stability, and magnetic properties have been investigated throughly using x-ray diffraction (XRD), differential scanning calorimetry (DSC), and vibrating sample magnetometry (VSM). XRD analysis of the as-milled powders revealed that the lattice parameter and the crystallite size of α-Fe phase lies in between 0.2850-0.2972 nm and 3–14 nm; whereas the same for γ-Ni lies in between 0.3550-0.3608 nm and 8–41 nm, respectively, during milling. The thermal analysis of the as-milled powders suggests that the onset temperature of crystallization increases as Fe content decreases. The thermomagnetic measurement of the heat treated powders has revealed the TC of α-Fe phase in x = 0.3 to be 590 K and that of γ-Ni phase in x = 0.4 to be 375 K. The maximum magnetic entropy change has been estimated to be 0.159 Jkg-1K−1 in x = 0.3, while that of x = 0.4 has been found to be 0.695 Jkg-1K−1 at an applied magnetic field of 19.9 kOe.

Characterization of nanostructured magnetic alloy based on Ni-Co-Mn produced by mechanical synthesis

Nanostructured Ni2MnCo alloy samples were prepared from pure elemental powders by Mechanical Alloying (MA) using a high-energy planetary ball mill. The obtained powders were characterized with XRD, SEM, laser diffraction granulometry and VSM techniques in order to study the microstructural, morphology, particle size distribution and magnetic properties as a function of milling time. The XRD patterns of as-milled powders revealed the formation of the main stage solid solution of Ni2MnCo with fcc structure phase after 24 h of MA. With increasing milling time from 0.5 hr to 50 hr, it is observed that the lattice parameter increases from 3.60 to 3.78 Å as well as an increase of microstrain from 0.17 to 0.41%, whereas the particle and crystallite size decreases down to 3.50 µm and 13 nm respectively. The mixture loses magnetization during the milling process due to the combined effects of crystallites size reduction and the dissolution of the antiferromagnetic compound (Mn) within the host lattice of the alloy. The very low values of the remanence ratio (Mr/Ms) ([1.2E-3, 1.7E-3]), as well as the very low values of the coercive field (≈ 1 Oe), were observed after 16 h of milling, which means that the alloy is magnetically saturated exhibiting a very soft magnetic behavior.

Effect of nanostructure on phase transformations during heat treatment of 2024 aluminum alloy

In this work, we studied the transformations involving the coherent (θ”/S”), semicoherent (θ’/S’), and incoherent (θ/S) precipitates (θ = Al 2 Cu, S = Al 2 CuMg) formed during the heat treatment of an annealed nanostructured powder of Al 2024 produced by cryogenic milling. These precipitates form over a wide temperature range (300–500 °C) depending on the chemical composition. They influence grain growth during sintering and may facilitate the formation of a fully dense nanostructured material. Mechanical milling was performed for 20 h at a cryogenic temperature to obtain nanostructured particles. The structural evolution and morphology of the particles during the heat treatment were investigated for three particle size ranges (<25, 25–45, and 45–90 μm). Heat treatment of the milled powder was performed at three different temperatures (475, 500, and 525 °C) for 5, 10, 15, and 20 min. Morphological analysis of the as-milled particles using scanning electron microscopy indicated that the milling process was not completed. X-ray diffraction analysis yielded the θ and S volume fractions for the heat-treated and as-milled powders. DSC analysis indicated the precipitation and dissolution of GP (Guinier-Preston zone), coherent, and incoherent precipitates during heating of the as-atomized and milled powders. Accumulation of the deformation energy during milling is suggested to lead to an early transformation of the S and θ phases in the finer powder.

Effect of milling time, MWCNT content, and annealing temperature on microstructure and hardness of Fe/MWCNT nanocomposites synthesized by high-energy ball milling

Nanocrystalline pure Fe and Fe/MWCNT nanocomposites powders with 0.25, 0.5, 1, and 10 wt% MWCNT contents were synthesized by high-energy ball milling (HEBM). The as-milled powders were cold-compacted and annealed at 400 °C and 600 °C for 1 h in Ar atmosphere. The effect of ball milling on pristine MWCNT and Fe/MWCNT composite powders was also investigated as a function of milling time up to 20 h. The physical properties of MWCNT were imaged by scanning electron microscopy (SEM) and transmission electron microscopy (TEM) before and after HEBM. The structural damage of MWCNT as a function of milling time and MWCNT content was studied using Raman spectroscopy. The structural characterization of MWCNT and Fe/MWCNT composites was conducted by X-ray diffraction (XRD) as a function of milling time, MWCNT content, and annealing temperature. The chemical properties of the synthesized composite powders were investigated using X-ray photoelectron spectroscopy (XPS). The microhardness test was performed to assess the effect of milling time, annealing temperature, and MWCNT content on the mechanical properties. The results indicated that after the ball milling process, the structure of MWCNT was destroyed, and the formation of the amorphous carbon phase was observed, which was confirmed by XRD and TEM analyses. In addition, decreased defect and carbon intensity ratios (ID/IG) were calculated from the Raman results with longer ball milling processes, which is attributed to the destruction of carbon bonds. The XPS results confirmed the presence of FeC bonds as a result of the formation of carbide phases. A fine dispersion of precipitated carbides determined by TEM is found to promote the grain size stability below 100 nm in the nanocrystalline Fe matrix. The results from the micro-hardness tests showed that Orowan particle strengthening resulting from the carbide formation, as well as grain size hardening, is an important contributor to strengthening in Fe/MWCNT composites.

High-temperature mechanical and thermochemical properties of NbMoTaW refractory high-entropy alloy coatings produced via Nano Particle Deposition System (NPDS)

In this study, we investigated the oxidation resistivity and mechanical properties of NbMoTaW refractory high-entropy alloy (HEA)-based coatings at high temperatures. The coating layers were produced using mechanically alloyed HEA powders via Nano Particle Deposition System (NPDS). The as-milled powder is comprised of W-rich BCC1 and NbMoTa-rich BCC2 phases. After the deposition process, the W-rich BCC1 phase remained, while NbMoTa-rich BCC2 phases were transformed into complex NbMo-rich and Ta-rich oxides. Consequently, the NbMoTaW RHEA composite coating exhibited outstanding oxidation resistivity and high nanoindentation hardness at high temperatures compared to that of commercial coating materials, possibly owing to the combination of the W-rich solid solution phase and internal oxides.

The Cu Matrix Strengthened by TiH₂-C In-Situ Synthesized via Mechanical Milling and Spark Plasma Sintering.

The present work is focused on the fabrication and the investigation of microstructures of copperbased TiC nanocomposites produced by mechanical milling in a high energy planetary ball mill. TiH₂, carbon and copper powders were used as starting materials in which In-Situ reaction between carbon and TiH₂ occurs to form TiC nanoparticles. The mixture powders of Cu-TiH₂-C were milled for 12 h at 450 rpm in Argon gas. Annealing treatment process at 950 °C for 2 h was applied for as-milled composite powders to enhance In-Situ reaction. The consolidation of composite powders was conducted by spark plasma sintering under uniaxial pressing of 70 MPa. Sintering procedure was done at 950 and 1000 °C for 5 min. The results indicated that as TiC nanoparticles are formed after sintering at 950 °C and the TiC particles are increased up at higher sintering temperature of 1000 °C. Fracture surface of sintered samples shows ductile mode. HR-TEM image showed the crystal size of copper was about 10 nm for sample sintered at 1000 °C. The hardness and relative density of the nanocomposites increase when increasing sintering temperature.